Clinical application of a surgical navigation system based on virtual thoracoscopy for lung cancer patients: real time visualization of area of lung cancer before induction therapy and optimal resection line for obtaining a safe surgical margin during surgery

Background

We have developed a surgical navigation system that presents virtual thoracoscopic images using computed tomography (CT) image data, as if you are observing intra-thoracic cavity in synchronization with the real thoracoscopic view. Using this system, we made it possible to simultaneously visualize the ‘area of lung cancer before induction therapy’ and the ‘optimal resection line for obtaining a safe surgical margin’ as a virtual thoracoscopic view. We applied this navigation system in the clinical setting in operations for lung cancer patients with chest wall invasion after induction chemoradiotherapy.

Methods

The proposed surgical navigation system consisted of a three-dimensional (3D) positional tracker and a virtual thoracoscopy system. The 3D positional tracker was used to recognize the positional information of the real thoracoscope. The virtual thoracoscopy system generated virtual thoracoscopic views based on CT image data. Combined with these two technologies, patient-to-image registration was performed in two patients, and the results generated a virtual thoracoscopic view that was synchronized with the real thoracoscopic view.

Results

The operations were started with video-assisted thoracic surgery (VATS), and the navigation system was activated at the same time. The virtual thoracoscopic view was synchronized with the real thoracoscopic view, which also simultaneously indicated the ‘area of lung cancer before induction therapy’ and the ‘optimal resection lines for obtaining a safe surgical margin’. We marked the optimal lines using an electric scalpel, and then performed lobectomy and chest wall resection with a sufficient surgical margin using these landmarks. Pathological examinations confirmed that the surgical margin was negative. No complications related to the navigation system were encountered during or after the procedures.

Conclusions

Using this proposed navigation system, we could obtain a ‘CT-derived virtual intra-thoracic 3D view of the patient’ that was aligned with the thoracoscopic view during surgery. The accurate identification of areas of cancer invasion before induction therapy using this system might be a useful for determining optimal surgical resection lines.

Psoas muscle mass in patients undergoing lung cancer surgery: a prognostic difference between squamous cell carcinoma and adenocarcinoma

BACKGROUND

Psoas muscle mass is a surrogate marker for sarcopenia: a depletion of skeletal muscle mass. This study was conducted to elucidate the prognostic significance of the psoas muscle index (PMI: cross-sectional area of the bilateral psoas muscle at the umbilical level on computed tomography/height² [cm²/m²]) in patients undergoing surgery for lung squamous cell carcinoma (SCC) and lung adenocarcinoma (ADC).

METHODS

One hundred and sixty-five patients with SCC and 556 patients with ADC who underwent R0 resection between 2007 and 2014 were reviewed for analysis. In SCC patients, the mean value (standard deviation) of the PMI was 6.15 (1.49) in men and 4.65 (1.36) in women. Among ADC patients, the PMI was 7.12 (1.60) in men and 5.29 (1.22) in women. Clinicopathological characteristics as well as the survival were evaluated.

RESULTS

The PMI was associated with the age, body mass index (BMI), and serum albumin. In the multivariable Cox regression analysis, after adjusting for age, BMI, serum albumin, sex, pathological stage, and diffusing capacity for carbon monoxide, the PMI showed a significant association with the overall survival (OS) and disease-free survival (DFS) in SCC patients (hazard ratios 0.50 and 0.56, 95% confidence intervals 0.39-0.65 and 0.45-0.71, respectively). On the other hand, in ADC patients, the PMI had no impact on the OS or DFS.

CONCLUSIONS

The PMI was significantly associated with the survival of lung SCC patients, but not of lung ADC patients, suggesting the presence of a previously unidentified relationship between skeletal muscle and lung SCC progression.

Primary peritoneal carcinoma with late-phase pulmonary metastases: a case report

Background

Primary peritoneal carcinoma (PPC) is a very rare and aggressive type of malignancy with a poor prognosis.

Case presentation

A 66-year-old woman was referred to our hospital with two pulmonary nodules that developed after PPC resection and postoperative adjuvant chemotherapy administered 5 years earlier. Computed tomography revealed a 1.3-cm-sized nodule in the left lung with a small airspace in the posterior basal segment and a 0.9-cm-sized solid nodule in the apico-posterior segment that grew slightly within a 2-month period. 18F-Fluorodeoxyglucose-positron emission tomography of these lesions revealed respective maximum standardized uptake values of 7.11 and 2.46. Her serum cancer antigen-125 level remained within the normal range, despite elevation before the first surgery. The posterior basal segment and superior division were subjected to anatomical segmentectomy. An intraoperative frozen section examination could not distinguish metastatic PPC from primary lung cancer. Immunopathologically, the two nodules were identified as metastatic PPC.

Conclusions

Our findings suggest that PPC patients may develop late-phase thoracic recurrence that is difficult to diagnose clinically after initial treatment in a potentially resectable setting.

Hydrogen water alleviates obliterative airway disease in mice

OBJECTIVE

Bronchiolitis obliterans syndrome arising from chronic airway inflammation is a leading cause of death following lung transplantation. Several studies have suggested that inhaled hydrogen can protect lung grafts from ischemia-reperfusion injury via anti-inflammatory and -oxidative mechanisms. We investigated whether molecular hydrogen-saturated water can preserve lung allograft function in a heterotopic tracheal allograft mouse model of obliterative airway disease METHODS: Obliterative airway disease was induced by heterotopically transplanting tracheal allografts from BALB/c donor mice into C57BL/6 recipient mice, which were subsequently administered hydrogen water (10 ppm) or tap water (control group) (n = 6 each) daily without any immunosuppressive treatment. Histological and immunohistochemical analyses were performed on days 7, 14, and 21.

RESULTS

Hydrogen water decreased airway occlusion on day 14. No significant histological differences were observed on days 7 or 21. The cluster of differentiation 4/cluster of differentiation 3 ratio in tracheal allografts on day 14 was higher in the hydrogen water group than in control mice. Enzyme-linked immunosorbent assay performed on day 7 revealed that hydrogen water reduced the level of the pro-inflammatory cytokine interleukin-6 and increased that of forkhead box P3 transcription factor, suggesting an enhancement of regulatory T cell activity.

CONCLUSIONS

Hydrogen water suppressed the development of mid-term obliterative airway disease in a mouse tracheal allograft model via anti-oxidant and -inflammatory mechanisms and through the activation of Tregs. Thus, hydrogen water is a potential treatment strategy for BOS that can improve the outcome of lung transplant patients.

Evaluation of intra-tumoral blood feeding to predict the effect of induction therapy in patients with locally advanced lung cancer

There is little known about predictors of the effects of induction therapy in locally advanced lung cancer, including superior sulcus tumors. We analyzed whether intra-tumoral blood feeding could predict a pathologic complete response (pCR). Patients who underwent induction therapy followed by surgery for locally advanced lung cancer were retrospectively reviewed. The intra-tumoral blood feeding was defined by the CT value (HU, Hounsfield unit), which was calculated by subtracting the non-enhanced value from the contrast-enhanced value (divided into the early and delayed phase) at the maximum diameter of the tumor on dynamic CT. The cases were classified, according to the efficacy of induction therapy, into the pCR and residual tumor (pRT) group. There were 38 cases of T3 and 12 of T4; the induction therapy consisted of chemoradiotherapy in 39 patients, chemotherapy in 6, and radiotherapy in 5. A pCR was obtained in 15 (30%) patients. The mean CT values of the early and delayed phases in the pCR group were 14.8 and 30.7 HU, while those in the pRT were 15.3 and 32.2 HU, respectively. A logistic regression analysis revealed that a smaller tumor size (< 42 mm) was a non-significant predictor of a pCR (p = 0.09); the maximum standardized uptake value on FDG-PET and the CT values on the early and delayed phases of dynamic CT were not associated with the achievement of a pCR. In conclusion, intra-tumoral blood feeding of the locally advanced lung cancer did not predict the effects of induction therapy, whereas smaller sized tumors tended to show a better response.

The tumor doubling time is a useful parameter for predicting the histological type of thymic epithelial tumors

PURPOSE

We assessed the utility of the tumor doubling time (TDT) for predicting the histological type of thymic epithelial tumors.

METHODS

We retrospectively reviewed 130 patients with thymic epithelial tumors who underwent computed tomography two or more times before surgery. The patients were divided into low-risk thymoma (types A, AB and B1), high-risk thymoma (types B2 and B3) and thymic carcinoma (thymic carcinoma and thymic neuroendocrine tumor) groups. In the 96 patients who showed tumor enlargement, the relationship between the histological type and the TDT of the tumor was investigated.

RESULTS

The study population included 55 men and 41 women from 26 to 82 years of age. The TDT of the thymic carcinoma group (median 205 days) was significantly shorter in comparison to the low-risk thymoma (median 607 days) and high-risk thymoma (median 459 days) groups. No significant differences were observed between the low-risk thymoma and high-risk thymoma groups. When we set the cutoff time for differentiating thymic carcinoma group from thymoma at 313 days, the sensitivity and specificity were 83.8% and 82.1%, respectively.

CONCLUSIONS

The TDT is a useful parameter for differentiating between thymoma and thymic carcinoma group.

Verification of T descriptor with consolidation size for sub-centimeter non-small cell lung cancer

PURPOSE

In the most recent (eighth) edition of the TNM classification, the clinical T descriptor has been adapted to measure the consolidation size of sub-solid lung cancer. Sub-centimeter non-small cell lung cancer (NSCLC) has thereby been subclassified into three groups: Tis, T1mi, and T1a; however, the revision has not been validated well. Thus, we investigated the clinicopathological characteristics and long-term oncological outcomes of sub-centimeter NSCLCs based on the solid size.

METHODS

The subjects of this retrospective review were 99 patients who underwent complete resection for NSCLC with ≤ 1 cm in consolidation size on computed tomography (CT). Survival was reanalyzed after reclassification according to the new TNM classification.

RESULTS

This cohort consisted of 14 patients with cTis tumors, 18 with cT1mi tumors, and 67 with cT1a tumors. Among the patients with tumors classified as cT1a, two had lymph node metastasis and two had vascular invasion. The cumulative incidences of recurrence at 5 and 10 years were 0% for cTis/cT1mi tumors, and 4.5% and 6.1% for cT1a tumors, respectively.

CONCLUSIONS

There may be pathological and survival differences between cTis/cT1mi tumors and cT1a tumors, but not between cTis tumors and cT1mi tumors.

Clinicopathologic Features of Thymoma With the Expression of Programmed Death Ligand 1

BACKGROUND

Programmed death ligand 1 (PD-L1) is reportedly expressed in various malignancies and is considered a prognostic factor. We attempted to reveal the usefulness of the PD-L1 expression as a prognostic factor in patients with thymoma.

METHODS

Eighty-one patients with thymoma who underwent surgical resection between 2004 and 2015 were retrospectively reviewed. The PD-L1 expression was evaluated by immunohistochemistry and stratified by the proportion of positive tumor cells. Strong membranous reactivity of the PD-L1 antibody in 1% or more of tumor cells was considered "positive." The association between the PD-L1 expression and the clinicopathologic features was investigated.

RESULTS

The PD-L1 expression was positive in 22 patients (27%) and negative in 59 patients (73%). The PD-L1 positivity was significantly associated with type B2 and B3 thymoma (p < 0.001) and stage III and IV disease (p = 0.048). In addition, PD-L1 positive tumors showed a significantly higher maximum standardized uptake value than PD-L1 negative tumors (p = 0.026). The 5-year disease-free survival rate was 82% in PD-L1 positive patients and 88% in PD-L1 negative patients, showing no significant difference (p = 0.57). Furthermore, PD-L1 positivity was not an independent prognostic factor for the disease-free survival on a Cox proportional hazards analysis (p = 0.59).

CONCLUSIONS

A strong expression of PD-L1 in thymoma was significantly associated with type B2 and B3 and higher pathologic stages. In addition, PD-L1 positivity was associated with an increased maximum standardized uptake value of the tumor. However, patients with PD-L1 positive thymomas did not show a significantly worse prognosis than patients with PD-L1 negative tumors.

Prognostic impact of tumour size in completely resected thymic epithelial tumours

OBJECTIVES

The T descriptor of thymic epithelial tumours proposed by the International Association for the Study of Lung Cancer and the International Thymic Malignancy Interest Group as well as the Masaoka-Koga system is defined by the anatomical extent of primary tumours, regardless of their size. However, the prognostic significance of tumour size in thymic epithelial tumours has not been fully elucidated.

METHODS

We evaluated the prognostic significance of tumour size in 154 consecutive patients with thymic epithelial tumours including 124 thymomas, 21 thymic carcinomas and 9 neuroendocrine tumours, who underwent complete resection between 2001 and 2014.

RESULTS

Among all tumours, the median tumour size was 4.9 cm. The median thymoma, thymic carcinoma and neuroendocrine tumour sizes were 4.8, 5.7 and 5.8, respectively, although the differences were not significant. In survival analysis, the 5- and 10-year overall survival (OS) and recurrence-free survival (RFS) rates for all patients were 91 and 81%, and 80 and 69%, respectively. Under the stratification of tumour size, no trend was observed for OS, whereas RFS showed stepwise deterioration as tumour size increased. For 119 patients with Stage I disease, RFS showed deterioration as tumour size increased. Multivariate analysis revealed that tumour size >4.0 cm was an independent prognostic factor for worsening RFS (P = 0.03).

CONCLUSIONS

Patients with tumours >4.0 cm showed significantly worse outcomes in RFS compared with those with smaller tumours. This relationship was also noted in patients with Stage I disease.

Collaborative operation with cardiovascular surgeons in general thoracic surgery

OBJECTIVES

The aim of this study was to investigate the feasibility and safety of our surgical experiences conducted in collaboration with cardiovascular surgeons at our institution.

METHODS

From May 2002 to December 2015, among 3595 general thoracic surgeries, 75 (2.1%) operations were carried out collaboratively with cardiovascular surgeons at Nagoya University Hospital. We investigated the surgical procedures, manipulated organs, morbidity and mortality, completeness of surgical resection, and prognosis of these 75 cases.

RESULTS

The study cohort consisted of 56 males and 19 females, ranging in age from 18 to 79 years (median 60 years). Fifty-eight patients had a malignant disease, and 17 had a benign disease. Out of 75 collaborative surgeries, 53 (71%) were scheduled cases (cardiovascular surgeons' support was considered to be necessary preoperatively), and 22 (29%) were emergent cases (cardiovascular surgeons' support was considered to be necessary intraoperatively). No 30- or 90-day mortality was observed. Respiratory failure, defined as the requirement of mechanical ventilation or non-invasive positive pressure ventilation for ≥5 days, was the most common morbidity (n = 14, 18%). Forty-three patients (78%) out of 55 with thoracic neoplasms achieved microscopic complete resection. The resection status of the remaining 12 (22%) was microscopic residual tumor.

CONCLUSION

Collaborative surgeries with cardiovascular surgeons at our institution were feasible. High-quality surgeries with a good balance between safety and completeness of resection are important not only for treatment, but also in terms of education for general thoracic surgeons.

Marginal pulmonary function is associated with poor short- and long-term outcomes in lung cancer surgery

We sought to determine the short- and long-term prognoses among ‘marginal-risk’ non-small cell lung cancer patients who have a predicted postoperative- (ppo) forced expiratory volume in the first second (FEV₁) of 30–60% and/or a ppo-diffusing capacity of the lung for carbon monoxide (DL_CO) of 30–60%. The present study included 73 ‘marginal-risk’ and 318 ‘normal-risk’ patients who underwent anatomical resection for clinical stage I lung cancer between 2008 and 2012. The rates of postoperative morbidity, prolonged hospital stay, and overall survival were assessed. Postoperative morbidity occurred in 35 (48%) ‘marginal-risk’ patients and 66 (21%) ‘normal-risk’ patients, and 17 (23%) ‘marginal-risk’ patients and 20 (6%) ‘normal-risk’ patients required a prolonged hospital stay. The three- and five-year survival rates were 79% and 64% in the ‘marginal-risk’ patients and 93% and 87% in the ‘normal-risk’ patients, respectively. A ‘marginal-risk’ status was a significant factor in the prediction of postoperative morbidity (odds ratio [OR] 2.97, p < 0.001), the rate of prolonged hospital stay (OR 3.83, p < 0.001), and overall survival (hazard ratio 2.07, p = 0.028). In conclusion, ‘Marginal-risk’ patients, who are assessed based on ppo-values, comprise a subgroup of patients with poorer short- and long-term postoperative outcomes.

Pulmonary metastasis from urothelial carcinoma of the upper urinary tract 29 years after nephrectomy

Background

Late pulmonary metastasis from urothelial carcinoma (UC) of the upper urinary tract is extremely rare.

Case presentation

A 76-year-old man was referred to our hospital due to an abnormal shadow on chest X-ray. He had a history of left nephrectomy with a diagnosis of UC in the renal pelvis 29 years previously. Computed tomography showed a mass lesion in the right middle lobe of the lung that measured 4.9 cm in diameter. A transbronchial biopsy revealed the tumor to be metastatic pulmonary UC, and he underwent right middle lobectomy of the lung.

Conclusion

Long-term postoperative follow-up of patients with UC might be necessary after radical nephrectomy.

Monoiodoacetic acid induces arthritis and synovitis in rats in a dose- and time-dependent manner: proposed model-specific scoring systems

OBJECTIVE

In a rat monoiodoacetic acid (MIA)-induced arthritis model, the amount of MIA commonly used was too high, resulting in rapid bone destruction. We examined the effect of MIA concentrations on articular cartilage and infrapatellar fat pad (IFP). We also established an original system for "macroscopic cartilage and bone score" and "IFP inflammation score" specific to the rat MIA-induced arthritis model.

DESIGN

Male Wistar rats received a single intra-articular injection of MIA in the knee. The amount of MIA was 0.1, 0.2, 0.5, and 1 mg respectively. Articular cartilage was evaluated at 2-12 weeks. IFP was also observed at 3-14 days.

RESULTS

Macroscopically, low MIA doses induced punctate depressions on the cartilage surface, and cartilage erosion proceeded slowly over 12 weeks, while higher MIA doses already induced cartilage erosion at 2 weeks, followed by bone destruction. MIA macroscopic cartilage and bone score, OARSI histological score, and Mankin score increased in a dose- and time-dependent manner. The IFP inflammation score peaked at 5 days in low dose groups, then decreased, while in high dose groups, the IFP score continued to increase over 14 days due to IFP fibrosis.

CONCLUSIONS

Punctate depressions, cartilage erosion, and bone destruction were observed in the MIA-induced arthritis model. The macroscopic cartilage and bone scoring enabled the quantification of cartilage degeneration and demonstrated that MIA-induced arthritis progressed in a dose- and time-dependent manner. IFP inflammation scores revealed that 0.2 mg MIA induced reversible synovitis, while 1 mg MIA induced fibrosis of the IFP body.

Not single but periodic injections of synovial mesenchymal stem cells maintain viable cells in knees and inhibit osteoarthritis progression in rats

OBJECTIVE

We investigated the effects of single or repetitive intra-articular injections of synovial mesenchymal stem cells (MSCs) on a rat osteoarthritis (OA) model, and elucidated the behaviors and underlying mechanisms of the stem cells after the injection.

DESIGN

One week after the transection of the anterior cruciate ligament (ACL) of wild type Lewis rats, one million synovial MSCs were injected into the knee joint every week. Cartilage degeneration was evaluated with safranin-o staining after the first injection. To analyze cell kinetics or MSC properties, luciferase, LacZ, and GFP expressing synovial MSCs were used. To confirm the role of MSCs, species-specific microarray and PCR analyses were performed using human synovial MSCs.

RESULTS

Histological analysis for femoral and tibial cartilage showed that a single injection was ineffective but weekly injections had significant chondroprotective effects for 12 weeks. Histological and flow-cytometric analyses of LacZ and GFP expressing synovial MSCs revealed that injected MSCs migrated mainly into the synovium and most of them retained their undifferentiated MSC properties though the migrated cells rapidly decreased. In vivo imaging analysis revealed that MSCs maintained in knees while weekly injection. Species-specific microarray and PCR analyses showed that the human mRNAs on day 1 for 21 genes increased over 50-fold, and increased the expressions of PRG-4, BMP-2, and BMP-6 genes encoding chondroprotective proteins, and TSG-6 encoding an anti-inflammatory one.

CONCLUSION

Not single but periodic injections of synovial MSCs maintained viable cells without losing their MSC properties in knees and inhibited osteoarthritis (OA) progression by secretion of trophic factors.

Clinical evaluation of a new tumour-node-metastasis staging system for thymic malignancies proposed by the International Association for the Study of Lung Cancer Staging and Prognostic Factors Committee and the International Thymic Malignancy Interest Group

OBJECTIVES

The tumour-node-metastasis classification has been widely used as a guide for estimating prognosis, and is the basis for treatment decisions in patients with malignant tumours. The International Association for the Study of Lung Cancer Staging and Prognostic Factors Committee and the International Thymic Malignancy Interest Group have proposed a new staging system for thymic malignancies. However, its validity has not been fully established. In this study, we assessed the system's utilities and drawbacks.

METHODS

We reviewed 154 consecutive patients with thymic epithelial tumours who underwent complete resection at our institution, and compared their characteristics and outcomes when classified according to the proposed system with those when classified under the Masaoka-Koga system.

RESULTS

The proportion of patients with Stage I disease increased remarkably to 77.3% when using the proposed system because of the reclassification of Masaoka-Koga stages II and III diseases. Among 69 patients with Type A, AB or B1 thymoma, 68 tumours (98%) were reclassified as Stage I disease. Moreover, the proportion of Stage III and IV tumours increased in concordance with Types B2, B3 thymomas and thymic carcinoma. Under the proposed new system, the recurrence-free survival rates showed significant deterioration with increasing stage, while the overall survival curves did not.

CONCLUSIONS

The newly proposed classification for thymic malignancies does not serve as a prognostic prediction model for overall survival but served as a significant imbalance of stage distribution in our cohort. However, it appears to be beneficial, especially in clinical settings and recurrence-free survival analysis.